Why do tanks need Determination stat still when they have Tenacity?

[Megguido]

I'll speak from the perspective of maining PLD for almost three years now.

Determination has proven to be a wonderful stat for me, reason being that it has boosted my Clemency and Holy Spirit to the point I felt it worthwhile. It also increases my baselines appreciably, but I have no illusions about ever making it to the "99th Percentile" on FFLogs or snatching the "big d**k DPS" crown from WAR.

As for "metas" and such, I really pay no attention to them. I'll probably dodge a tomato or two by saying this, but I personally have no use for Dir Hit melds on a tank. Build your character in a way that works for you. If you want to do straight DH melds left and right, be my guest. If you want to meld Tenacity over Determination because that's what works best for the way you play your tank job, go nuts.

Well, yes and no.

Going Tenacity instead of Determination sure is a DPS loss, but a minor one. Meld are worth a couple hundreds of substats, which will boost your damage by like 2-4% depending on which substat you choose. Basically, if you don't parse and optimize, you won't see any difference between full DET and full TEN melds. So, yeah, meld what makes you feel good unless you're going for the 90th+ percentile on fflogs. I could go full Tenacity melds on the left side, and only lose around 0.5% - 1% damage.

But, Strength melds on the right side are a significant increase to a tank's DPS. I mean, meld whatever you want, but at least please put STR melds on your accessories. STR materias are cheap and gives way more damage than any Crit/Det/DH materia.

[...]

As was previously mentioned, Tenacity just doesn't scale in quite the same way in terms of boosting one's DPS. I don't relegate it to the status of a dump stat, but it's not my priority, especially when you consider PLD arguably has the best damage mitigation and CDs of all three tank jobs.

This might be a popular misconception, because PLD got a shield and shiny armor, but it's actually the tank that has the least personnal damage mitigation. Both WAR and DRK outclass PLD on this aspect.

[...] I think the less we preached to the choir about what others "should" be doing with their builds and focused more on optimizing our own builds instead, the collective sanity of our community would benefit immensely. But that's just my opinion. :V

Basically this. Melding DET, DH, TEN etc... won't make your DPS skyrocket. It's much more about optimizing the way you play rather than the way you build. Sure, building with the "right" stats will allow for a higher DPS, and is part of optimizing. But, the BiS gearset won't compensate for playing poorly.